You have to think the story through, and you have to stick the landing.

Thinking the story through means just that: you have to be able to answer questions the reader will ask in a satisfying way. You have to think of the questions as you’re laying your story out, and if the story doesn’t answer the question, then you have more work to do.

(Sometimes, this means you may have to turn into a junior scientist. Comic books are often fantastical, hence, science-fiction. You have to learn your science decently well in order to propel your fiction. You don’t have to be extremely accurate—look at superheroes—but you have to know enough to at least make the reader not want to ask the question. This is why we do research, often much more than we need to. We have to understand the subject matter in order to find the shortcuts, because even though they’re shortcuts, they still have to make sense to the reader.)

As long as you think the story through and answer the questions, the second part shouldn’t be as difficult.

Sticking the landing means having an ending that works. It would be awesome if the ending was kickass as well, but in the end, if the ending works, it could very well end up being kickass.

I find it useful to actually find the ending of the story before I have much of anything else. Either that, or some kind of important sequence that can lead to an ending. Then I can work the story backwards, or just skip the middle altogether and go to the beginning, making sure the story gets directed to the ending I laid out.

If you do these two things, your storytelling should improve. If you don’t, readers will stay away from your work.